1. Field of the Invention
This invention relates to an apparatus for conveying an incumbent person, more particularly to an apparatus for conveying a disabled person or an invalid (herein frequently referred to simply as a "person") lying on a bed, operating table, stretcher or the like and unable to stand or walk.
2. Prior Art Statement
For conveying such an incumbent person it is generally necessary to somehow bring a conveyance means near or in contact with the person and then to cause an operating force to act on the person. Conventional methods that are extensions of techniques for transporting heavy loads have been developed for this purpose and involve, for example, using an apparatus resembling a forklift to lift the person together with his bed or using a crane-like device suspended from the ceiling for lifting the person by means of a sling constituted of belts, a net or a sheet. In addition, one particularly excellent method that has been developed involves inserting a loading plate between the person and the supporting surface (e.g. the top of a bed) and then conveying the person on the plate. In this method, the loading plate has belts wound thereon and the belts are paid out synchronously with the movement of the plate, thus eliminating slippage at the plate surfaces in contact with the person and the supporting surface. The principle involved is shown in FIGS. 6(A), (B) and (C). The loading plate 31 is arranged in upper and lower segments which are separated by spacers 32 and respectively have belts 33a and 33b wound thereon. When moving toward the incumbent person 36 (FIG. 6(A)), the belt 33a on the upper segment rotates counterclockwise while the belt 33b on the lower segment rotates clockwise. The reference numerals 34 and 35 respectively denote the main body of the apparatus and the support (e.g. bed) on which the person is lying. The upper belt 33a moves beneath the person 36 (FIG. 6(B)) and then after the person has been completely loaded on the upper segment of the loading plate 31 as shown in FIG. 6(C) the plate 31 is returned to the main body 34. At this time, the lower belt 33b only is rotated counter clockwise so that the person 36 can be conveyed without slippage between the contacting surfaces. A large number of apparatuses for conveying incumbent persons which operate on this principle have been developed. These are described, for example, in U.S. Pat. Nos. 3,947,902, 3,967,328, 4,073,016, 4,077,073 and 4,680,818, U.S. patent application Ser. No. 031,668, and Japanese Patent Publication Nos. 47(1972)-34477, 56(1981)-16659, 56(1981)-24536 and 56(1981)-34298. While all of these relate to belt-type conveyance systems, they propose various systems for driving and controlling the plates and belts. As a system which has actually been marketed there can be mentioned the Full Automatic Stretcher DR-520 sold by Takara Belmont K.K. of Japan.
These systems are capable of conveying a person with relatively small driving power but entail a problem as to safety. As shown in FIG. 7, the loading plate is constituted in two segments and spacers are ordinarily provided between them at their opposite ends. Thus it is not possible to provide belts on the end portions and these portions are used for the provision of a driving means or the like for the loading plate. Therefore, when one of these portions strikes against the person to be conveyed, the person is apt to be injured because of the large amount of friction arising between the end portion and the person. Moreover, where a loading plate of large area is used, it is necessary to provide spacers at several locations. This makes it impossible to use only a single belt and the usual practice is to provide a plurality of belts in parallel. This increases the risk of the person's hair or fingers getting caught under the lateral edge of a belt in the unbelted region between two adjacent belts. It is also undesirable from the point of sanitation since it provides openings into which dirt, loose hairs and the like can be drawn. For avoiding these problems it might be thought advisable to use one of various other conceivable conveyance methods in which the conveyance means is brought in direct contact with the person to be conveyed. However, from the points of safety and of reducing pain and discomfort to the person, the belt system is considered to be the best.